In the combustion of a fuel such as coal, oil, peat, waste, etc., in a combustion plant such as a power plant, a hot process gas is generated that contains among other components, sulphur oxides, such as sulphur dioxide, SO2. Sulphur dioxide is an environmental pollutant. Hence, it is necessary to remove at least a portion of the sulphur dioxide from the process gas before the process gas can be released into the atmosphere.
EP 0 162 536 discloses a wet scrubber in which an absorption liquid containing limestone is brought into contact with a process gas to absorb at least a portion of the content of sulphur dioxide, SO2, of the process gas. The absorbed sulphur dioxide forms, in the wet scrubber, gypsum, which may be disposed of or used as a useful product in the production of gypsum wall board.